Dodge Ram Truck 1500-2500-3500. Manual — part 1617
P0841-LR PRESSURE SWITCH RATIONALITY (CONTINUED)
14.
LOW LINE PRESSURE
In the EATX DTC EVENT DATA recorded earlier, compare the Line Pressure and the Desired Line Pressure.
Is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?
Yes
>> Repair as necessary to correct low line pressure. Check for low fluid level. Check the Primary Oil Filter
seal for a split, crack, or improperly installed. Refer to the Service Information for the proper installation
procedure. If the fluid level and Primary Oil Filter are OK, check the Main Regulator Valve in the Oil
Pump per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Go To 15
15.
(T50) LR PRESSURE SWITCH SENSE CIRCUIT SHORT TO OTHER CIRCUITS
Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid/TRS Assembly harness connec-
tor.
Disconnect all PCM harness connectors.
Measure the resistance between the (T50) LR Pressure Switch Sense
circuit and all other circuits in the Transmission Solenoid/TRS Assem-
bly harness connector.
Is the resistance below 5.0 ohms between the (T50) LR Pres-
sure Switch Sense circuit and all other circuit(s) in the Trans-
mission Solenoid/TRS Assembly harness connector?
Yes
>> Repair the (T50) LR Pressure Switch Sense circuit for a
short to other circuit(s).
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1.
No
>> Go To 16
16.
ROAD TEST THE VEHICLE
With the scan tool, clear the DTC and road test the vehicle.
Try to duplicate the conditions in which the DTC originally set using the EATX DTC EVENT DATA recorded earlier.
Did the DTC P0841 reset?
Yes
>> Replace the Transmission Solenoid/TRS Assembly per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Go To 17
21 - 400
AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS
DR/DH
P0841-LR PRESSURE SWITCH RATIONALITY (CONTINUED)
17.
INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
>> Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Test Complete.
DR/DH
AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS
21 - 401
P0845-2C HYDRAULIC PRESSURE TEST
21 - 402
AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS
DR/DH
P0845-2C HYDRAULIC PRESSURE TEST (CONTINUED)
For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE -
SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
•
When Monitored:
In any forward gear with engine speed above 1000 RPM shortly after a shift and every minute thereafter.
•
Set Condition:
After a shift into a forward gear, with engine speed above 1000 RPM, the PCM momentarily turns on element
pressure to the Clutch circuits that don’t have pressure to identify the correct Pressure Switch closes. If the
Pressure Switch does not close 2 times, the DTC sets.
Possible Causes
LINE PRESSURE SENSOR
TRANSMISSION FLUID CONTAMINATION
RELATED DTC’S PRESENT
TRANSMISSION SOLENOID/TRS ASSEMBLY
EXCESSIVE DEBRIS IN OIL PAN
POOR LINE PRESSURE SENSOR CONNECTION
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT OPEN
TRANSMISSION CONTROL RELAY DTCS PRESENT
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
TRANSMISSION SOLENOID/TRS ASSEMBLY
INTERNAL TRANSMISSION
POWERTRAIN CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS AND TESTING).
Theory of Operation
The Transmission Control System tests the pressure switches when they are off. The test verifies that the switches
are operational (They will close with pressure applied). The Transmission Control System verifies that the switch
closes when the corresponding element is applied. If a switch fails to close, it is re-tested. If it fails the second test,
the DTC will set, the MIL will illuminate and the transmission system will default to the orderly Shutdown routine.
Diagnostic Test
1.
DETERMINING IF RELATED DTC’S ARE PRESENT
With the scan tool, check for other transmission DTC’s
Is there any Loss of Prime, Transmission Control Relay, and/or Line Pressure Sensor DTCs present?
Yes
>> Refer to the Transmission category and perform the appropriate symptom. If the DTC, P0944-LOSS OF
PRIME is present, perform its respective test first.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No
>> Go To 2
DR/DH
AUTOMATIC TRANSMISSION - 545RFE - ELECTRICAL DIAGNOSTICS
21 - 403
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